CVE-2020-7616 — express-mock-middleware
MEDIUMCVE-2020-7616 is a medium-severity (CVSS 5.3) CWE-1321 vulnerability in express-mock-middleware. 1 public exploit reference exists, so weaponization risk is real. No vendor fix is recorded yet; mitigation options are listed below.
Improperly Controlled Modification of Dynamically-Determined Object Attributes in express-mock-middleware
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
CVE-2020-7616 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.
Where this sits among everything scored
Of 385,386 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.
Real-World Exposure
How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.
express-mock-middlewarenpmDescription
express-mock-middleware through 0.0.6 is vulnerable to Prototype Pollution. Exported functions by the package can be tricked into adding or modifying properties of the Object.prototype. Exploitation of this vulnerability requires creation of a new directory where an attack code can be placed which will then be exported by express-mock-middleware. As such, this is considered to be a low risk.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | express-mock-middleware | all versions | No fix |
Affected Products
express-mock-middlewareexpress-mock-middleware_projectResearch use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for express-mock-middleware, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Remediation status
No patched version of express-mock-middleware has shipped for CVE-2020-7616 yet. Where your build allows, override or pin the dependency away from the vulnerable range, and apply any maintainer-recommended mitigation.
Mitigate without a patch
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
Frequently Asked Questions
Is CVE-2020-7616 in your dependencies?
Find it across npm, including transitive dependencies.